The surface area of a spirit is 7.85π ft. What is the radius of this spear?

To find the radius of the sphere, we can use the formula for the surface area of a sphere:

Surface Area = 4πr^2

Given that the surface area is 7.85π ft, we can plug this value into the formula:

7.85π = 4πr^2

Divide both sides by 4π:

r^2 = 7.85 / 4

r^2 = 1.9625

Take the square root of both sides to find the radius:

r = √1.9625

r = 1.4

Therefore, the radius of the sphere is 1.4 feet.